The AS3340 chip is Alfa’s modern equivalent of the famous CEM3340 voltage-controlled oscillator.
It provides Ramp, Pulse/Square, and Triangle outputs, has inputs for oscillator sync, is temperature compensated and stable, and provides excellent 1V/Oct tracking. In short, it’s everything you need from an analog oscillator, on a chip. There hasn’t been a better design than the 3340.
Please note that Alfa recommend a 51K resistor on the pulse output in place of the 10K resistor that the CEM3340 used. There seem to be some subtle differences between the Alfa chips and CEM originals, particularly with respect to pulse width. We’ve had one or two reports of difficulties replacing dead/missing CEM3340s with AS3340s. For this reason, if you’re repairing a vintage synth, we recommend using CEM3340 Rev.Gs rather than replacing with Alfa AS3340s.
These are brand new chips fresh from the Alfa Rpar semiconductor factory in Riga, Latvia.
Rob Hordijk wrote a very complete guide on tuning the AS3340, which offers a lot of useful information beyond what’s in the datasheet. Definitely worth a read if you’re using this chip.
You could also have a look at our page studying CEM3340 oscillator designs from famous synths.